[alsa-devel] snd-fireworks requires larger period sizes than FFADO

[Clemens Ladisch]

Dominic Sacré wrote:
> I'm trying to use an Echo AudioFire 4 with the snd-fireworks driver.
> With FFADO the device works reasonably well at a period size of
> 64 samples (on a PREEMPT_RT kernel), whereas with snd-fireworks the
> lowest possible period size seems to be 256 samples.
>
> The lowest achievable analog roundtrip latency seems to be around 19ms
> (at 2x256 frames), as opposed to 8.3ms with FFADO (at 2x64). Are there
> any known limitations of the snd-fireworks driver in this regard?

At the moment, the driver uses a minimum period size of 5 ms.

You could try reducing INTERRUPT_INTERVAL and the parameter to
snd_pcm_hw_constraint_minmax() in sound/firewire/amdtp-stream.c, and
recompiling the driver.


Regards,
Clemens